Braun tube for television receiver apparatus



Dec. 22, 1936. M. KNOLL BRAUN TUBE FOR TELEVISION RECEIVER APPARATUSFiled March 6, 1934 R O I m 9 E ,A v 7 5 2 23% 3/ M J Z 0 Z W 1 o o 2 Am n collector andfocussing means.

Patented. ea. 22, 1936 PATENT; OFFICE TUBE FOR TELEVISION RECEIVERAPPARATUS Max Knoll, Berlin, Germany, assignor to TelefunkenGesellschaft fiir Drahtloae Telegraphic m. b. 11., Berlin, Germany, acorporation of Application March 6, 1934, Serial No. 714,263

In Germany March 13, 1933 2 Claims.

The present invention is concerned with' a- Braun tube capable of use ina television receiver, and it concerns more particularly the ways andmeans by which the electrodes, which I are confined inside the tube andintended for ray generation, ray control and optionally also for ray orpencil focussing, are to be disposed and secured with respect to oneanother. According to the earlier art these constituent parts werefastened by spot welding to the wires which are brought to the seals orlead-ins .for the electrodes. However, this mode of support is attendedwithrthe drawback that it is rather diflicult to cause the variouselectrodes to occupy the exact positions relative to one another whichthey are to occupy in the actual operation of the tube. Another factoris that during the heating I of the tube, which is necessary before itis severed from the vacuum pump, the said wires are liable to bend orwarp'with the result that, no

20 matter how careful the adjustment during the assembly and mounting ofthe tube, considerable and serious defects as regards adjustment arise25 drawbacks are obviated by that at least two of the electrodes servingfor ray generation and modulation are fitted upon one or more commonsupporting rods or bolts and are spaced apart the requisite distancesbysuitable spacer members. This form of construction makes it possibleto observe and insure the necessary distances during the work ofmounting with the greatest accuracy, and it moreover represents a formof construction that will undergo only very slight and negligibledeformation during the heating of the tube by high frequency currentsfor removing occluded gasses. Another object of the invention is to usethe said supporting bolts also for the purpose of carrying the ray Thespacing apart of these latter means and their distance from the anode ofthe tube is also secured by the aid of spacers.

An exemplified embodiment of the present in- V 45 vention, in which allof the electrodes employed for ray generation and ray modulation as wellas for focussing'the ray-pencil are alined on two supporting bolts andare kept' apart by spacers, is -illustrated schematically in Fig. 1 ofthe-attached drawing which forms a part of the application. Referringto'this figure, I denotes the glassenvelope of a Braun tube which isprovided atgone end with a reentrant stem II and 55 the press l2.Surrounding the stem' Hts a metal collar l3 which,'ior instance, mayconsist of two semi-circular sheet-metal straps clamped fast by the aidof screws or rivets I to the stem ll. Attached to the said collar l3 aretwo supporting bolts or rods i5 and I6,

which have portions that are exactly parallel to one another. Pins I1and I8 pass through insulation tubes l9 and 20 which, for instance,

may consist of quartz, alumina or magnesia. The various electrodes ofthe Braun tube are each furnished with a flange provided with two boresthrough which project the supporting bolts or rods l5, l6, and theinsulation tubes I9, 20. These electrodes are: a support 2| for theelectron-emissive coat of the cathode, a control or Wehnelt cylinder 22designed to influence the intensity of the stream of electrons, and adisc anode 23. Above theseelectrodes there is further shown in thedrawing an electrostatic focussing device for the cathode-ray pencilpassing throughthe anode 23.v This focussing device consists of threecylindrical tubes 24, 25, 26, which are also furnished with flanges.These electrodes just like the ones before mentioned and serving for raygeneration and ray-pencil modulation, are also mounted on the supportingbolts l5, l6. Also between the pins l1, l8 serving as abutments orbearing points, and the flange of cathode 2|, there are interposed twoinsulation spacer pieces 35. The supply leads brought to the severalelectrodes fitted upon the supporting bolts are sealed into the squashi2 which also contains the supply leads for the heaterwinding 31 of thecathode. This form of construction is suited especially in the casewhere the several electrodes present a comparative] low potentialdiflerence therebetween.

in those cases where the voltages between the various electrodes aregreater, a slightly dlfierent arrangement is used for the lead-in wires,

' and this arrangement is shown in Fig. 2 of the being united with'aspecial lead-in or seal in dicated at 40, or else distinct laterallead-ins are provided as indicated at M by which the elec- I trodes ofhigher potential are connected. In this latter instance, connection, forinstance, be-

. tween electrode 26 and the supporting member i5 is simply establishedby that the insulating piece 3! is omitted.

Deflector plates 42, 43 are also disclosed in Fig. 2 and these may bedisposed and secured onto the supports [5, it in a manner similar to themounting of the electrodes 2| to 26 inclusive.

Instead of the outwardly curved or offset form 7 of the support rods orbolts l5, I6 shown in the drawing, they may take the form of straightrods if the collar 83 is furnished with two radial parts or flanges ofsuch size that the supporting bolts are sufficiently spaced apart in thedirection at right angles to the tube axis. In either instance thesupporting bolts l5 and "5 are 1 preferably secured on the collar I3 insuch a waythat their mutual position, at leastso far as that inlongitudinal sense is concerned, can be adjusted to each other. This isfeasible, for instance, by that the supporting bolts are fastened to'theradial flanges of the collar 83 by the aid of screws, and by that thebores for one of the screws is slot-shaped as shown in the drawing.

Any deviation that may be found from exactparallelism in the sense ofthe longitudinal axis of the two supporter bolts may then be correctedby turning one of the bolts about the circular screw holes 38, while thescrew passing through the' slot-formed bore 39 must be loosenedslightly. Any departure from the true parallel position in the directionat right angles to the plane laid through the drawing is eliminated bythat a thin spacers are inserted at the place of bore 38 or bore 39.

The flanges of the electrodes shown in the drawing need not necessarilybe circular, indeed,

they may be of any shape other than circular or be provided with boresof the kind found in perforated sheets. In this manner the aggregatesurface of the metal parts contained in the Braun tube can bediminished, and this means a correspondingly reduced risk of evolutionof gases from these parts and greaterease in heating the tube during theoutgassing process.

What I 'claim is: 1. A Braun cathode-ray tube comprising-a plurality ofvertically disposed support rods, a

4 cylindrical indirectly-heated cathode disposed 'with its axis inparallel relation to the support rods, tubular sleeves of insulatingmaterial surrounding said support rods, a cylindrical indirectly-heatedcathode disposed with its axis in parallel relation to the support rodsand having a plurality of laterally-extending flanges, each flange beingprovided with an opening through which a support rod and its insulatingsleeve are passed, a plurality of cooperating electrodes.

mounted above said cathode in'spaced axial alignment and havinglaterallyextending flanges similar to those of the cathode and similarlymounted on the same support rod insulated sleeves, and means carried bysaid support rod. insulating sleeves and interposed between the flangesof successive electrodes for insulating the several electrodes from eachother 4 and maintaining them in fixed spaced relation.

' MAX KNOLL.

